1. Technical Field
The present invention relates to a solid-state image sensing device.
2. Background Art
Published Japanese Translation No. 2008-546313 of the PCT International Publication discloses a solid-state imaging device that comprises a plurality of pixels, at least two of pixels each having (a) a photodetector, (b) a charge-voltage conversion region that configures a floating capacity portion and (c) an input to an amplifier, and a connection transistor that configures a switch for selectively connecting between the charge-voltage conversion regions.
According to the conventional solid-state imaging device, the connection transistor is turned on, whereby it is possible to perform a pixel mixing (charge-domain binning) that read out a charge of the photodetector of the at least two of pixels with mixing. Additionally, the connection transistor is turned off, whereby, similar to a usual solid-state imaging device not having the connection transistor, it is possible to perform to read out a charge of the photodetector of the at least two of pixels without mixing.
Results of the study of the inventors, in the conventional solid-state imaging device, find out that an image quality of the captured image is reduced due to generation of a leak current via the connection transistor turned off. Namely, in the conventional solid-state imaging device, when the connection transistor is turned off, a charge of the charge-voltage conversion region of an adjacent pixel, which is supposed to be blocked by the connection transistor, flows as leak current into the charge-voltage conversion region of the pixel where a signal is to be read out via the connection transistor. As a result, the image quality is reduced due to generation of a white floating or a noise in the image caused by the leak current.
It is an object of aspects of the present invention to improve an image quality in a solid-state imaging device that includes a connection transistor that connects or disconnects floating capacity portions.